Clock Input Timing
4 Clock Input Timing
This section provides the clock input DC and AC electrical characteristics for the device.
4.1
DC Electrical Characteristics
Table 6 provides the clock input (CLKIN/PCI_SYNC_IN) DC timing specifications for the MPC8347EA.
Table 6. CLKIN DC Timing Specifications
Parameter
Input high voltage
Condition
Symbol
Min
Max
Unit
—
—
VIH
VIL
IIN
2.7
–0.3
—
OVDD + 0.3
V
V
Input low voltage
0.4
10
10
CLKIN input current
PCI_SYNC_IN input current
0 V ≤ VIN ≤ OVDD
μA
μA
0 V ≤ VIN ≤ 0.5 V or
IIN
—
OVDD – 0.5 V ≤ VIN ≤ OVDD
PCI_SYNC_IN input current
0.5 V ≤VIN ≤ OVDD – 0.5 V
IIN
—
50
μA
4.2
AC Electrical Characteristics
The primary clock source for the MPC8347EA can be one of two inputs, CLKIN or PCI_CLK, depending
on whether the device is configured in PCI host or PCI agent mode. Table 7 provides the clock input
(CLKIN/PCI_CLK) AC timing specifications for the device.
Table 7. CLKIN AC Timing Specifications
Parameter/Condition
CLKIN/PCI_CLK frequency
Symbol
Min
Typical
Max
Unit
Notes
fCLKIN
tCLKIN
—
15
0.6
40
—
—
—
66
—
MHz
ns
1, 6
—
2
CLKIN/PCI_CLK cycle time
CLKIN/PCI_CLK rise and fall time
CLKIN/PCI_CLK duty cycle
CLKIN/PCI_CLK jitter
Notes:
tKH, tKL
tKHK/tCLKIN
—
1.0
—
2.3
60
ns
%
3
—
150
ps
4, 5
1. Caution: The system, core, USB, security, and TSEC must not exceed their respective maximum or minimum operating
frequencies.
2. Rise and fall times for CLKIN/PCI_CLK are measured at 0.4 and 2.7 V.
3. Timing is guaranteed by design and characterization.
4. This represents the total input jitter—short term and long term—and is guaranteed by design.
5. The CLKIN/PCI_CLK driver’s closed loop jitter bandwidth should be < 500 kHz at –20 dB. The bandwidth must be set low to
allow cascade-connected PLL-based devices to track CLKIN drivers with the specified jitter.
6. Spread spectrum clocking is allowed with 1% input frequency down-spread at maximum 50 KHz modulation rate regardless
of input frequency.
MPC8347EA PowerQUICC II Pro Integrated Host Processor Hardware Specifications, Rev. 12
Freescale Semiconductor
13
FREESCALE [ Freescale ]
